Injectors



May 21, 1968 c. H. MUELLER INJEGTORS 4 Sheets-Sheet 1 Filed April 15, 1967 (an! H. Nadir/z lmza.

May 21, 1968 c. H. MUELLER 3,384,018

INJECTORS Filed April 13, 1967 4 Sheets-Sheet 2 FIG.6.

May 21, 1968 c. H. MUELLER INJECTORS 4 Sheets-Sheet 5 Filed April 13, 1967 y 21, 1963 c. H. MUELLER 3,384,018

INJECTORS Filed April 13, 1967 4 Sheets-Sheet 4 United States Patent 3,384,018 INJECTORS Carl H. Mueller, Pasadena Hills, Mo., assignor to M cNe1l Corporation, Akron, Ohio, a corporation of Ohio Continuation-impart of abandoned application Ser. No. 549,311, May 11, 1966. This application Apr. 13, 1967,

Ser. No. 632,882

16 Claims. (Cl. 103-2) ABSTRACT OF THE DISCLOSURE A lub-ricant injector of the type comprising a pump cylinder having a series of outlet ports spaced along its length and a pump plunger movable in the cylinder for forcing out measured charges of lubricant successively from the ports is provided with means for varying the amount of the charge delivered from each port, this means comprising a control cylinder and a control plunger movable in the cotnrol cylinder conjointly with the pump plunger for venting part of the charge delivered from each outlet port, the phase of the control plunger relative to the pump plunger being adjustable for varying the amount of the charge which is vented.

This application is a continuation-in-part of my copending application, Ser. No. 549,311, filed May 11,

1966, now abandoned.

Background of the invention This invention relates to injectors, and more particularly to lubricant injectors.

The invention is particularly concerned with lubricant injectors of the type such as shown in US. Patent 2,783,- 713 comprising a pump cylinder having a series of outlet ports spaced at intervals along its length, and a pump plunger slidable in the cylinder toward and away from one end of the cylinder, the plunger having a lateral port spaced from its respective end and a longitudinal passage for communication from the space in the cylinder ahead of the plunger and the lateral port, the arrangement being such that a measured charge of lubricant is forced out of the cylinder through each successive outlet port as the lateral port passes each outlet port. The amount of the charge delivered through each outlet port and thence through a lubricant delivery line to a point of lubrication is equal to the displacement of the plunger from the instant the lateral plunger port first comes into communication with the outlet port to the instant it passes out of communication with the outlet port.

Summary of the invention Among the several objects of this invention may be noted the provision of an injector, and particularly a lubricant injector of a type described above, which is adapted for varying the amount of the charge delivered from each of the outlet ports; the provision of such an injector wherein the adjustment of the charge delivered from each outlet port may be easily and rapidly made at the place of installation of the injector; the provision of such an injector which is adapted for use in high pressure lubrication systems; and the provision of such an injector which is reliable in operation and accurate in delivery even as to small charges. While the invention "ice has been developed principally for injection of lubricant, and is so described hereinafter, it will be understood that it is not limited to use for lubricant injection but may find use for delivering charges of pumpable materials other than lubricants. Other objects and features will be in part apparent and in part pointed out hereinafter.

An injector constructed in accordance with the present invention is comprised of a pump cylinder having a lateral outlet port and a pump plunger movable therein toward and away from one end of the cylinder constituting its forward end. The plunger has a lateral port spaced from its forward end and a longitudinal passage for communication from the space in the cylinder forward of the plunger to the lateral plunger port. The plunger, on a forward stroke thereof, and as the lateral plunger port passes the outlet port, is adapted to force a charge of material to be injected from the space through the longitudinal passage and the lateral plunger port to the outlet port, the latter having a delivery exit and a vent exit. In addition, means are provided for controlling the vent exit to vent part of the charge via the vent exit, the remainder of the charge being delivered via the delivery exit.

Brief description of the drawings FIG. 1 is a plan of an injector made in accordance with the invention;

FIGS. 2-5 are elevations of the four faces of an elongate square-cross-section pump body of the injector;

FIG. 6 is a vertical longitudinal section of the injector, taken on line 6-6 of FIG. 1;

FIG. 7 is an enlarged fragment of FIG. 6;

FIGS. 812. are sections taken on lines 88 to 12-12 of FIG. 7, but on the smaller scale of FIG. 6;

FIGS. 13 and 14 are sections on lines 13-13 and 14-14- of FIG. 1;

FIG. 15 is a vertical longitudinal section of an alternative embodiment of the injector; and

FIG. 16 is a section on line 16-16 of FIG. 15.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Description of the preferred embodiments Referring to the drawings, first more particularly to FIG. 6, an injector made in accordance with this invention is shown to comprise a pump cylinder 1 having a series of outlet ports spaced at intervals along its length. As shown herein, there are six such ports, but it will be understood that the number of outlet ports is not critical. The six outlet ports are designated Pl-P6. As illustrated, the cylinder 1 is vertically disposed. A pump plunger 3 is slidable in the cylinder toward and away from the lower end of the cylinder, which may be referred to as its forward end. The plunger has a lateral port 5 spaced from its lower (forward) end 7, and a longitudinal passage 9 extending from its lower (forward) end 7 to the port 5 for communication from the space 11 in cylinder 1 below 3 plane, and the interval between them (indicated at X in FIG. 7) also equals the width of the groove 13. By interval is meant the distance in longitudinal direction along the length of the cylinder and plunger between the leading edge of any port (the lower edge) and the trailing edge (the upper edge) of the next port in the series.

The space 11 in cylinder 1 is adapted to be maintained primed with lubricant (or other material to be handled by the injector) via a check-valved inlet 17 at the forward (lower) end of the cylinder, this inlet having connected thereto a supply line S from a suitable source of lubricant under pressure. Means for actuating the plunger 3 through a forward (downward) stroke and a return (upward) stroke is shown to comprise an air motor generally designated 19. The arrangement is such that, on a forward (downward) stroke of the plunger, individual charges of lubricant are successively forced out of the cylinder to ports P1-P6 as the groove 13 passes by the inner end of each successive port. With the diameter of the inner ends of the ports and the intervals between the inner ends of the ports equal to the width of the groove '13, the groove comes into communication with the inner end of each successive port as it passes out of communication with the inner end of the preceding port, and remains in communication with the inner end of any given port as it sweeps across the latter. This provides for a maximum discharge from cylinder 1 via each port equal to the displacement of the plunger from the instant the groove 13 first comes into communication with the inner end of the port to the instant it passes out of communication with the inner end of the port. However, in accordance with this invention, means is provided for adjustably venting at least one of the ports to vent off part of the discharge from that port, thereby to control the amount delivered from that port. As herein illustrated, such control over the discharge from ports P2P5 is provided, and the means for effecting the control is shown to include a second cylinder 21, which may be referred to as the control cylinder, extending parallel to and alongside cylinder 1, and a plunger 23, which may be referred to as the control plunger, slidable in the control cylinder and movable conjointly with plunger 3.

The cylinders 1 and 21 are conveniently formed by longitudinally boring an elongate block 25 of generally square cross section. This block, referred to as the pump body, extends centrally of a lubricant reservoir 27 from the top of the reservoir nearly but not quite to the bottom of the reservoir. The reservoir comprises a cylindric barrel 29, which may be made of a suitable transparent plastic, an upper end head 31 and a lower end head 33. The reservoir is secured to the bottom of the air motor 19, extending downward therefrom, the air motor comprising a cylinder 35 having an integral upper end head 37 and an outwardly extending flange 39 around its lower end provided with a bracket 41 (see FIG. 1) for mounting the assembly of the motor and reservoir in vertical position. The air motor cylinder 35 has a lower end head constituted by a shouldered plug 43 inserted in the lower end of cylinder 35, the lower end of the plug being accommodated in an opening 45 in the upper end head 31 of the reservoir. The upper end of the pump block or body 25 fits in a recess 47 in the bottom of the plug, and the parts are held in assembly by means of screws 49 extending through a collar 51 on the pump body adjacent its upper end and through the upper end head 31 of the reservoir and threaded in the bottom end of the air motor cylinder 35. The longitudinal edges of the pump body are rounded off except at the upper end of the pump body where they are left intact as indicated at 53 for being clamped by the collar 51.

A piston 55 is slidable in the air motor cylinder 35. The plungers 3 and 23 extend upward out of cylinders 1 and 21 through suitable seals in openings 57 and 59 in the plug 43 and have their upper ends connected to the piston 55, which constitutes a common driver for the two plungers. Passages for supplying compressed air to and venting air from the upper and lower ends of the air motor cylinder for reciprocating the air motor piston are indicated at 61 and 63. It will be understood that supply and venting of air via these passages is under control of a, suitable conventional air motor valve (not shown). The arrangement is such that on supplying compressed air to the upper end of air motor cylinder 35 via passage 61 and venting the lower end of the cylinder 35 via passage 63, piston 55 is driven downward to drive plunger 3 downward through a pumping stroke and simultaneously to drive plunger 23 downward, and on supplying compressed air to the lower end of cylinder 35 via passage 63 and venting the upper end of the cylinder 35 via passage 61, piston 55 is driven upward to return the plungers.

The lower end of cylinder 1 is counterbored as indicated at 65, and inlet 17 is threaded therein. This inlet comprises a tubular fitting having an extension 67 through a central opening 69 in the lower end head 33 of the reservoir 27, a nut 71 being threaded up on extension 67 against head 3. The inlet fitting 17 has an axial passage 73 and radial ports 75 for communication from this passage to the reservoir below the lower end of the pump body 25. In the inner end of the fitting is a ball check valve 77, held captive by a pin 79, adapted to open upward on an upward (return) stroke of plunger 3 and to close on a downward stroke (a forward or pressure stroke) of plunger 3. The lower end of cylinder 21 is open to the reservoir.

The four side faces of the generally square cross section pump body are designated F1-F4, F4 being opposite F1, and F3 being opposite F2. Cylinder 21 is located between cylinder 1 and face F4. The first port P1 and the last port P6 are formed by drilling into the pump body 25 from face F1 (see FIGS. 6, 7 and 8). Port P2 is formed by drilling a hole 81 into the pump body from face F4 across cylinders 21 and 1, the inner end of this hole constituting the inner end of port P2, and by drilling a hole 83 into the pump body from face F2 at right angles to hole 81 intersecting the latter to the left of cylinder 1 as viewed in FIG. 9. Hole 83 constitutes a delivery exit. Portion 81a of hole 81 constitutes a vent exit. Port P3 is formed by drilling a hole 85 into the pump body from face F4 across cylinders 21 and 1, the inner end of this hole constituting the inner end of port P3, and by drilling a hole 87 into the pump body from face F3 at right angles to hole 85 intersecting the latter to the left of cylinder 1 as viewed in FIG. 10. Hole 87 constitutes a delivery exit. Portion 85a of hole 85 constitutes a vent exit. Port P4 is formed by drilling a hole 89 into the pump body from face F4 across cylinder 21 and 1, the inner end of this hole constituting the inner end of port P4, and by drilling a hole 91 into the pump body from face F2 at right angles to hole 89 intersecting the latter between cylinders 1 and 21 as shown in FIG. 1. Hole 91 constitutes a delivery exit. Portion 89a of hole 89 constitutes a vent exit. Port P5 is formed by drilling a hole 93 into the pump body from face F4 across cylinders 21 and 1, the inner end of this hole constituting the inner end of port P5, and by drilling a hole 95 into the pump body from face F3 at right angles to hole 93 intersecting the latter between cylinders 1 and 21 as shown in FIG. 12. Hole 95 constitutes a delivery exit. Portion 93a of hole 93 constitutes a vent exit.

The outer ends of ports P1 and P6 and the outer ends of the delivery exits 83, 87, 91 and 95 of ports P2-P5 are enlarged to accommodate an outwardly opening ball check valve 97 and a fitting for connection of a lubricant delivery line, the fitting holding the ball check valve in place. Lubricant delivery lines 9, 101, 103 and are connected at one end to the delivery exits of ports PZ-PS and at their other end to passages such as indicated at 107 in FIG. 14 in the bottom flange 39 of the air motor. These passages extend through the flange 39 and are adapted for connection to their outer (upper) ends of four delivery lines 99a, 101a, 103a and 105a in continuation of lines 99, 101, 103

and 105 extending to four different points of lubrication of an apparatus to be injection-lubricated. These correspond, for example, to lubricant delivery lines indicated at 37, 39, 41 and 43 in U.S. Patent 3,232,379 of Carl H. Mueller et al., issued Feb. 1, 1966, entitled Lubricating Apparatus. Lines 109 and 111 extend within the reservoir from ports P1 and P6 to ports 113 and 115 in the bottom flange 39 of the air motor, which are in communication with a failure indicator indicated in phantom at 117 in FIG. 1. This does not constitute a part of the present invention, being shown in the copending coassigned U.S. patent application of Carl H. Mueller et al., Ser. No. 425,707, filed J an. 15, 1965, entitled Lubricating Apparatus.

The control plunger 23 has a lateral vent port 119 spaced from its lower end 121 (its forward end) and a longitudinal passage 123 extending from its lower end to the port 19 for communication from vent port 119 to the cylinder 2 forward of (below) the plunger 23 and thence to the reservoir 27. The lateral vent port 119 is constituted by an annular groove 125 in the plunger 23 and radial passages 127 from the groove to the passage 123 (see FIG. 7). The width of groove 125 is equal to the width of groove 13. The control plunger 23, at its upper end, has a fixed connection 128 with the air motor piston 55, but the pump plunger 3, at its upper end, has an adjustable connection with the piston for the purpose of effecting longitudinal relative adjustment of the plungers for varying the phase of grooves 13 and 125. For purposes of establishing this adjustable connection, the piston 55 has a central threaded bore 129 with counterbores 131 and 133 at opposite ends of this bore. An adjustment screw 135 is threaded in bore 129. This screw has a head 137 at its inner end having a sliding fit in the counterbore 133, the upper end of the plunger 3 being keyed in this head as indicated at 139. A kerf 141 is provided in the upper (outer) end of the screw. A plug 143 is threaded in a central opening 145 in the upper end head 37 of the air motor cylinder. By removing this plug, a screw driver may be inserted through the opening 145 to turn the screw in one direction or the other, which results in axial shifting of the piston 55 in cylinder 35 and shifting of the plunger 23. Endwise movement of the piston relative to the screw is limited by the head 137 on the screw and a retaining ring 147 on the screw in counterbore 131. A friction plug 149 is provided in the screw for maintaining the adjustment.

FIG. 6 shows the piston 55 at the upper limit of its adjustment relative to screw 135 (determined by the engagement of retaining ring 147 with the inner end of the countcrbore 131), and in its fully retracted position. With the piston at this limit of its adjustment and in its fully retracted position, its forward (lower) end 7 is located immediately rearward of (above) a relief port 151 interconnecting cylinder 1 and cylinder 21. Groove 13 in plunger 3 is located rearward of (above) the first port P1, in communication with a clearance space 153 formed by an enlarged-diameter section of cylinder 1. A port 155 (see FIG. 7) at the forward (lower) end of this clearance space 153 interconnects cylinder 1 with a similar clearance space 157 in cylinder 21 formed by an enlargeddiameter section of the latter. A pressure relief port 159 interconnects the forward end of clearance space 157 and the reservoir 27. In the retracted position of plunger 3, plunger 23 is also retracted, and groove 125 in plunger 23 registers with port 159. Clearance spaces 153 and 157 are vented to atmosphere via a radial port 161 in plug 43 to an annular groove 163 in the plug, and a vent passage 165 in the plug from the annular groove.

The air motor piston 55 is slidable in the air motor cylinder between an upper limit determined by engagement of the upper end of the screw 135 with the inner end of plug 143 and a lower limit determined by engagement of the lower end of the head of the screw with plug 43. When the screw is turned (without turning the piston), the effect is to move the piston axially relative to the screw thereby shifting plunger 23 endwise relative to plunger 3 to adjust plunger 23 relative to plunger 3. As shown in FIGS. 6 and 7, with piston 55 at the upper limit of its adjustment relative to the plunger 3, plunger 23 is so positioned relative to plunger 3 that groove in plunger 23 slightly leads groove 13 in plunger 3 (i.e., groove 125 is located slightly below groove 13). On turning the screw to adjust the piston 55 down relative to the screw, plunger 23 is moved down relative to plunger 3, and the lead of groove 125 over groove 13 is increased.

Operation is as follows:

The reservoir 27 is in constant communication with a supply of lubricant under pressure (not shown) via passage 73 and ports 75 in the inlet fitting 17. Accordingly, the reservoir is maintained full of lubricant under the supply pressure (which may be 20 pounds per square inch, for example). Whenever the pump plunger 3 is retracted, the space 11 in cylinder 1 below the pump plunger is primed with lubricant, which enters this space via passage 73 in the inlet fitting 17 due to opening of ball check valve 77 when the plunger 3 is retracted. Some lubricant may also enter this space when the lower (forward) end 7 of plunger 3 is retracted past port 151 from the reservoir via the open lower end of cylinder 21 and port 151.

As shown in FIGS. 6 and 7, with piston 55 at the upper limit of its adjustment relative to screw 135, the groove 125 of the lateral port 119 in the control plunger 23 slightly leads the groove 13 of the lateral port 5 in the pump plunger 3. On a downstroke (a forward or pumping stroke of the air motor piston 55), the plungers 3 and 23 are driven downward in unison, with groove 125 leading groove 13. As plunger 3 moves downward, it blocks port 151 and ball check valve 77 closes to trap lubricant in the space 11 below the lower end of plunger 3.

With regard to the provision of relief port 151 in addition to the ball-checked inlet 17. when the pump plunger 3 is retracted, its lower (forward) end is rearward of port 151. As the plunger 3 is driven downward through a forward or pumping stroke, it blocks port 151 as the groove 13 of the lateral plunger port 5 comes into communication with the first outlet port P1. From this cut-off point on, exit of lubricant from space 11 via port 151 is blocked end, check valve 77 being closed, lubricant is forced out of space 11 via plunger passage 9. Any air that might be entrapped in the lubricant in the pump cylinder 1 is forced out via port 151 as the plunger moves from its retracted position to the stated cut-off point. Provision of the checkvalved inlet 17 at the forward end of the cylinder 1 results in priming (filling) of the cylinder 1 when the plunger 3 is retracted without creating a void (vacuum) in space 11, as would occur if port 151 were the only inlet to the cylinder 1. Provision of the port 151 results in accurate establishment of the cut-off point for start of delivery of lubricant from port P1, as might not be the case if checkvalved inlet 17 alone were provided. Thus, the provision of both check-valved inlet 17 and port 151 insures delivery of a full charge from port P1, and this is an advantageous feature.

When the lower end of plunger 3 passes by port 151 (thereby trapping lubricant in space 11), groove 13 in plunger 3 comes into communication with the first port P1 and, as the groove 13 sweeps by the port P1, a measured charge of lubricant is forced out of space 11 and delivered via passage 9 in plunger 3 and ports 15, groove 13, port P1, line 109' and port 113 to the failure indicator 117. The amount of this charge is equal to the displacement of the plunger 3 from the instant the groove 13 first comes into communication with port P1 to the instant it passes out of communication with port P1.

As soon as the groove 13 passes out of communication with the port P1, it comes into communication with port P2. As groove 13 sweeps by the port P2, it forces lubricant from space 11 upward through passage 9 and out through ports 15 and groove 13 in amount equal to the displacement of the plunger 3 from the instant groove 13 first comes into communication with port P2 to the instant it passes out of communication with port P2. Noting that groove 125 slightly leads groove 13, groove 125 comes into communication with vent exit 81a of hole 81 slightly before groove 13, and passes out of communication with vent exit 81a slightly after roove 13. During the interval in which both grooves 13 and 125 are in communication with vent exit 81a, lubricant forced upward from space 11 through passage 9 in plunger 3 is vented to the reservoir 27 via groove 125, ports 127, passage 123 in plunger 23 (and the outer end portion of hole 81). During the ensuing interval in which groove 13 is still in communication with vent exit 81a, but groove 125 is past vent exit 81a (and out of communication therewith), lubricant forced upward from space 11 through passage 9 in plunger 3 is forced out and delivered through the delivery exit 83 of port P2 and lines 99 and 99a. Thus, the amount of lubricant actually delivered through delivery exit 83 of port P2 and lines 99 and 99a to the respective points of lubrication corresponds only to the displacement of plunger 3 through the distance which groove 13 trails groove 125, not the displacement of the plunger 3 from the instant groove 13 first comes into communication with port P2 to the instant it passes out of communication with port P2. While lubricant is maintained under pressure in the reservoir 27, the venting back of lubricant to the reservoir occurs when groove 125 sweeps past the vent exit 31a (instead of delivery out through delivery exit 83 of port P2) because the pressure required to force lubricant out through delivery exit 83 of port P2 and lines 99 and 99a to the respective point of lubrication is higher than that required for such venting.

As soon as the groove 13 in the pump plunger passes out of communication with port P2, it comes into communication with port P3. As groove 13 sweeps by the port P3, it forces lubricant from space 11 upward through passage 9 and out through ports and groove 13 in amount equal to the displacement of plunger 3 from the instant groove 13 first comes into communication with port P3 to the instant it passes out of communication with port P3. However, since groove 125 slightly leads groove 13, groove 125 comes into communication with vent exit 85a of port P3 slightly before groove 13, and passes out of communication with vent exit 85a slightly after groove 13. As a result, the initial part of the lubricant discharge is vented back to the reservoir, and only a small amount of lubricant corresponding to the displacement of plunger 3 through the distance which groove 13 trails groove 125 is forced out and delivered through delivery exit 87 of port P3 and lines 101 and 101a.

On continued downward movement of plungers 3 and 23, groove 13 sweeps by ports P4, P5 and P6 and groove 125 sweeps by holes 89 and 93. Small charges of lubricant are delivered through delivery exits 91 and 95 of ports P4 and P5, in amount corresponding to the displacement of plunger 3 through the distance which groove 13 trails groove 125, in the same manner as small charges are delivered via ports P2 and P3, as above described. A full charge of lubricant is delivered via port P6, full charge meaning an amount corresponding to the displacement of plunger 3 from the instant groove 13 first comes into communication with port P6 to the instant it passes out of communication with port P6 (this being the same as for port P1). The piston 55 then reaches the lower end of its stroke (determined by engagement of the lower end of head 137 of screw 135 with plug 43), and is then returned to the upper end of its stroke (determined by engagement of the upper end of the screw 135 with plug 143).

By adjusting plunger 23 so that groove 125 has increased lead on groove 13 in plunger 3, the amount of lubricant delivered through the delivery exit of each of the ports P2P5 to the respective points of lubrication may be increased. The range of adjustment is such that the amount of lubricant delivered through the delivery exit of each of ports P2P5 may be varied through a relatively infinite range from a small fraction of a full charge to a full charge. Delivery of a full charge through the delivery exit of each of ports P2P5 is attained by adjusting plunger 23 relative to plunger 3 to the point where groove 125 leads groove 13 a distance such that groove 125 will pass out of commu ication with vent exits 81a, a, 89a and 93a as groove 13 comes into communication therewith. This full charge delivery position of plunger 23 relative to plun er 3 is indicated by the dotted line showing of the position of the lower end of the plunger 23 and groove in FIG. 7, and corresponds to the shifting of piston 55 to the lower limit of its adjustment with respect to screw (as determined by engagement of screw head 137 with the inner end of counterbore 133). With plunger 23 and groove 125 in the full charge position of adjustment, there is no venting of lubricant via the vent exits 81a, 85a, 89a, 93a, hence a full charge is delivered through the delivery exit of each of ports P2P5. With the plunger 23 in intermediate positions of adjustment, venting in intermediate amounts from ports P2P5 and delivery in intermediate amounts via ports P2P5 will occur, as will be apparent.

The plunger 23 leads the plunger 3 throughout the adjustment range. This has the desirable effect of pumping any trapped air back into the reservoir. Also, an acceleration is created whereby an impact occurs at the time of discharge through the outlet ports, which is beneficial to lubricant injection where a pulse is needed.

In the modified embodiment of the invention illustrated in FIG. 15, the injector is intended to be utilized in a high pressure lubrication system, such as for example, when it is desired to deliver accurate amounts of lubricant against 6,000 p.s.i.g. pressure. The modified injector is similar to the injector described above except that the reservoir 27 is eliminated and the lubricant vented through control plunger 23 is returned to the supply. In addition, the piston of the air motor 19 is given on the return (upward) stroke by the supply lubricant pressure acting on the faces of plungers 3 and 23, rather than by compressed air acting on the air motor piston.

Since the reservoir 27 is eliminated in the modified form of the injector, each of the vent exists 81, 85, 89 and 93 is sealed with a suitable plug 167 to prevent the. escape of vent lubricant. The forward (lower) end of the cylinder 1 is closed by an inlet fitting 169 having the supply conduit S connected thereto. A check valve 170 is interposed between the end of pump cylinder 1 and the inner face of plug 169. As best illustrated in FIG. 16, check valve 170 is comprised of a tubular body portion 171 having large and small coaxial bores 173 and 175. A ball 177 is maintained in the large bore 173 by a stop pin 179. The lower end of fitting 170 is provided with a pair of leg portions 181 and 182 which abut against the plug 169 and form a lateral passage between the end of cylinder 21 and the face of plug 169. A passage or slot 183 is provided between the legs 181 and 182. Therefore, on a forward (downward) stroke of the plungers 3 and 23 the vent lubricant is delivered via groove 119, passages 127 and 123, cylinder 21, passage 180 and slot 183 to the inlet of check valve 170 where it is drawn into the space 11 of pump cylinder 1 on the next return (upward) stroke of the plunger 3.

The air motor 19 is operated by air pressure on the forward (downward stroke and by lubricant pressure on the return (upward) stroke. Thus a single air inlet 185 is provided in the upper end head 37 of the cylinder 35 for supplying air to a piston 187 on its forward stroke. When the piston 187 reaches the end of its forward stroke, the air pressure is interrupted by an air Valve (not shown) and the piston is caused to return to the upper end of the cylinder 35 by lubricant pressure acting on faces 7 and 121 of plungers 3 and 23, respectively. Thus, forward movement of the piston 187 and plungers 3 and 23 is produced by :air pressure acting on the upper face of piston 187 and return movement is produced by lubricant pressure acting on faces 7 and 121 of plungers 3 and 23. It is possible to return the plungers and the piston in this manner because of the high pressure at which the lubricant is supplied to the injector. In all other respects, the modified embodiment of the injector operates substantially the same as that described above.

As noted above, it is contemplated that the dual plunger arrangement of the invention may be useful for injection systems other than lubricant injector systems. For example, it may be useful in a fuel injection system for an internal combustion engine, for injecting measured charges of fuel into the engine cylinders. In such case, the plungers would be driven from the engine in accordance with the speed of the engine, and the plunger 23 would be automatically adjusted to control the amount of the charge delivered by being shifted relative to plunger 3 by a vacuum control responsive to engine manifold vacuum. In the FIG. 15 embodiment, if the fuel pressure is high enough, the plungers may be driven in a forward direction by the engine in accordance with its speed but may be returned by the fuel pressure in the manner set forth above.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An injector comprising a pump cylinder having a lateral outlet port, a pump plunger movable in the cylin der toward and away from one end of the cylinder constituting its forward end, the plunger having a lateral port spaced from its forward end and a longitudinal passage for communication from the space in the cylinder forward of the plunger to said lateral plunger port, said plunger, on a forward stroke thereof, and as the lateral plunger port passes the outlet port, being adapted to force a charge of material to be injected from said space through said longitudinal passage and said lateral plunger port to said outlet port, said outlet port having a delivery exit and a vent exit, and means movable conjointly with said plunger for controlling said vent exit to vent part of said charge via said vent exit, the remainder of said charge being delivered via said delivery exit.

2. An injector as set forth in claim 1 wherein said control means is adjustable to vary the amount of said charge vented via said ven-t exit and hence to vary the amount of said charge delivered via said delivery exit.

3. An injector as set forth in claim 1 wherein said cylinder has a plurality of lateral outlet ports spaced at intervals along its length, said control means controlling the venting of part of the charge from each outlet port and hence the amount of the charge delivered via the delivery exit of each outlet port.

4. An injector as set forth in claim 3 wherein said control means is adjustable to vary the amount of the charge vented from each outlet port and hence to vary the amount of the charge delivered via the delivery exit of each outlet port.

5. An injector as set forth in claim 1 wherein said con trol means comprises a control cylinder and a control plunger movable in the control cylinder and interconnected with the pump plunger for conjoint movement therewith, said vent exit being in lateral communication with said control cylinder, and said control plunger having a lateral vent port adapted for communication with said vent exit as the control plunger moves with the pump plunger during the interval in which the lateral port in the pump plunger passes by the outlet port.

6. An injector as set forth in claim 5 wherein the interconnection between the plungers includes an adjustment for adjusting the phase of the vent port in the control plunger relative to the lateral port in the pump plunger for varying the amount of the charge vented via said vent exit and hence varying the amount of said charge delivered via said delivery exit.

7. An injector as set forth in claim 5 wherein said pump cylinder has a plurality of lateral outlet ports spaced at intervals along its length, the vent exits of said ports being in communication with said control cylinder, and said control plunger controlling the venting of part of the charge via the delivery exit of each outlet port.

8. An injector as set forth in claim 7 wherein a fiuid operated motor is provided for driving said plungers, said motor comprising a cylinder and a piston, said plungers being connected to said piston, the connection of one of said plungers to said piston being adjustable for varying the phase of the vent port relative to the lateral port in the pump plunger.

9. An injector as set forth in claim 8 wherein the connection between the pump plunger and the piston is the adjustable connection, and comprises a screw threaded in the piston and extending axially through the piston, the rearward end of the pump plunger being attached to the forward end of the screw.

10. An injector as set forth in claim 8 further comprising a reservoir for said material surrounding said cylinders, said vent port venting into said reservoir.

11. An injector as set forth in claim 10 wherein the forward end of the control cylinder is open to the reservoir, and the control plunger has a longitudinal passage extending from said vent port to the forward end of the control plunger.

12. An injector as set forth in claim 11 wherein the pump cylinder has a check-valved inlet at its forward end in communication with said reservoir.

13. An injector as set forth in claim 12 wherein the pump cylinder has a lateral relief port in communication with the reservoir located forward of the last outlet port, said pump plunger blocking said relief port as the lateral plunger port comes into communication with the first outlet port.

14. An injector comprising a pump cylinder having a.

series of lateral outlet ports spaced at intervals along its length, a pump plunger movable in the cylinder toward and away from one end of the cylinder constituting its forward end, the plunger having a lateral port spaced from its forward end and a longitudinal passage for communication from the space in the cylinder forward of the plunger to said lateral inlet port, said cylinder having a lateral relief port in communication with a supply of material to be injected located forward of the last outlet port of the series, a check-valved inlet in communication with said supply at the forward end of the cylinder, said plunger being movable forward through a pumping stroke from a retracted position wherein the forward end of the plunger is rearward of said lateral vent port, and blocking said lateral vent port as the lateral plunger port comes into communication with the first outlet port, and effecting closing of the check-valved inlet, whereupon individual charges of said material are successively forced out said space to the outlet ports as the lateral plunger port passes by each successive outlet port, any entrapped air in said material in said cylinder being forced out via said relief port as said plunger moves from its retracted position to the point where it blocks said relief port.

15. An injector as in claim 8 wherein said fluid-operated motor drives said plungers only on forward strokes thereof and the charge acting on the plunger faces drives them on return strokes.

16. An injector as set forth in claim 15 further comprising a lateral passage at the lower end of said control cylinder, said passage providing communication between 11 12 said control and pump cylinders, said vent port venting 2,686,476 8/1954 Klein et a1. 103-2 into said pump supply. 2,783,713 3/1957 Klein et a1, 1032 2,793,593 5/1957 Klein et a1. 103-2 References Cfled 2,808,779 10/1957 Mueller 103 2 UNITED STATES PATENTS 5 3,306,523 2/1967 NillSSOn 1032 1,128,643 2/1915 Wetmorc 1032 2 157 970 Rowland et 1 X Przmary Exammer. 2,360,093 10/1944 Ainslie 6t 81. 10337 X HENR F RADUAZ E 2,481,856 9/1949 Medhaug 103-4 Y xamme" 2,672,014 3/1954 Yarger 103--41 X 10 W. I. KRAUSS, Assistant Examiner. 

